Horse running through field

High Upside, High Downside Risk

by Roger Lyons

What do Lyphard, Fappiano, and Nureyev have in common? As ancestors of dams, each of these sires passes on respective traits that rub a lot of stallions the wrong way, but that contribute in favorable ways to the offspring of a lot of other stallions. We know this because of the high approval and high disapproval rates shown in the table of ancestor preferences for these three ancestors. In that respect, they represent a distinctive category of ancestors–a category for which stallion selection is faced with very high upside and very high downside risk.

Based on that table, there’s a 29% chance that a stallion whose name you pick out of a hat will have a higher-than-average strike rate with mares in descent of Lyphard; but there’s a 27% chance that a stallion chosen at random will have a lower-than-average strike rate with those mares.

Just a cursory look at the table suggests what a distinctive profile that is for an ancestor. Fappiano is similar, with a 27.5% approval rate and a 31% disapproval rate, and Nureyev has a 28% approval rate and a 26% disapproval rate. You can find other stallions with a similar profile. It’s not particularly rare, but it’s rarely this extreme.

In order for the stallion population to respond the way it does, the distinctive traits these three ancestors contribute–along with other ancestors of this statistical profile–would have to pass through to foals on a very consistent basis. Furthermore, in order to complement the contributions of a lot of stallions, but clash with the contributions of many others, those traits would have to be distinctive in character, but without being particularly idiosyncratic, as in the case of Graustark.

That much can be inferred from the numbers. As a numbers cruncher, I have no idea what traits are at issue in the contributions of Lyphard, Fappiano, and Nureyev and wouldn’t have the eye to discern them if they were pointed out to me. Still, the numbers say it’s something to consider.

3 comments to “High Upside, High Downside Risk”

  • Greg writes:

    I guess the issue for me would be how many of those “disapprovals” were severely rather than just mildly negative. Same for the “approvals,” of course.

  • Roger Lyons writes:

    Two considerations, Greg. First, I use a fairly strict statistical test for approval and disapproval, but, even more pertinent, it’s in the nature of these ancestors that stallions tend to do either very well or very poorly with them. So, there are very few marginal cases. Most of the disapprovals of Lyphard are like those of Storm Cat (2/30) and Mr. Greeley (0/32), and the approvals are like those of Stormy Atlantic (7/36) and Royal Academy (9/57). The exceptions are few. Cherokee Run is a marginal approval at 3/31. There’s not a single case of a marginal disapproval of Lyphard in this sample.

  • Greg writes:

    Interesting, good stuff. It would certainly pay to know what Lyphard doesn’t like.

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